The purpose of this research program is to examine the relationship between marital interaction patterns and conduct-related behaviors in preschool-aged conduct-problem children. Mediators of the link between marital hostility, antisocial behavior and poor peer relations are also sought, including (1) the role of social cognitive deficits and biases, and (2) psychophysiological processes. Observations of marital and parent-child interaction, peer interaction and children's reactions to interadult hostility and to a provocative peer situation will be conducted. Autonomic measures (cardiac interbeat interval, T-wave amplitude, ear and finger pulse transit time, finger pulse amplitude, skin conductance level, vagal tone & gross motor activity) synchronized to real-time behavioral observations will be obtained from the child during exposure to interadult conflict, peer provocation, and an attention-demanding task. The effects of marital hostility on social information processing, peer relations and antisocial behavior will be examined. Physiological models of conduct-problems will also be tested under conditions of interpersonal threat, relaxed conditions, and in an attention-demanding task. Two theoretical models will be tested in which marital hostility, sympathetic and parasympathetic nervous system reactivity to interpersonal threat and social cognitive biases and deficits are related to antisocial behavior and negative peer interaction.